Added "name" parameter to the help message.

In OS_IDENTITY_API_VERSION=3, the "openstack help service delete"
allows the user to remove a service based on the name of the
service. So, this patch includes name as positional argument.

Change-Id: Iae7cb0a82af3cdd4d88e0ed2eb651abf9af30fd9
Closes-Bug: #1566909

openstackclient/identity/v3/service.py

@@ -82,7 +82,7 @@ class DeleteService(command.Command):
         parser.add_argument(
             'service',
             metavar='<service>',
-            help='Service to delete (type or ID)',
+            help='Service to delete (type, name or ID)',
         )
         return parser